TRIGEN META-NAIL System

Tibial and Retrograde Femoral Nail

Femoral Nail

Threaded for enhanced fixation

The TRIGEN META-NAIL Retrograde Femoral Nail is the latest addition to the TRIGEN family of intramedullary nails. With a full range of sizes, the Retrograde Femoral Nail is a comprehensive approach to the treatment of femoral fractures. Enhanced fixation via threaded screw holes and polyethylene bushings offer better solutions for the fixation of complex fractures.

Indications

The TRIGEN META-NAIL Retrograde Femoral Nail is indicated for fractures of the femur including stable and unstable distal metaphyseal fractures, diaphyseal fractures, intra-articular fractures, peri-prosthetic fractures, non-unions, mal-unions and for the prophylactic nailing of impending pathological fractures.

Features

  • Multi-planar distal locking hole configuration for optimal fixation
  • Threaded screw holes and polyethylene bushings enhance fixation and minimize post-operative fragment translation
  • Nail cap locks most distal screw for additional fixation
  • Anatomic 2.0m AP Bow minimizes anterior cortical impingement and enhances fit
  • Elimination of distal Herzog Bend optimizes insertion site and facilitates easier implant insertion
  • Full range of sizes for a comprehensive and accurate approach to fracture fixation
  • Uses standard TRIGEN locking screws for system compatibility
  • Titanium alloy for strength, flexibility and biocompatibility

Tibial Nail

Threaded for enhanced fixation

The TRIGEN META-NAIL Tibial Nail is the latest addition to the TRIGEN family of intramedullary nails. With a full range of sizes, the Tibial Nail is a comprehensive approach to the treatment of tibial fractures. Enhanced fixation via threaded screw holes and polyethylene
bushings offer better solutions for the fixation of complex fractures.

Indications

The TRIGEN META-NAIL Tibial Nail is indicated for fractures of the proximal and distal third of the tibia, including the shaft, stable and unstable metaphyseal fractures, non-unions, mal-unions, and for the prophylactic nailing of impending pathological fractures.

Features

  • Enhanced multi-planar proximal locking hole configuration for optimal fixation
  • Threaded screw holes and polyethylene bushings enhance fixation and minimize post-operative fragment translation
  • Full range of sizes and 1cm increments for a comprehensive and accurate approach to fracture fixation
  • Internally threaded distal locking hole located 5mm from nail tip for enhanced
  • Fixation of extreme distal fractures
  • 2° distal bend facilitates implant passage and fit within the distal tibia
  • Nail cap locks most proximal screw for additional fixation
  • Up to 7mm of active compression possible through proximal dynamization slot
  • Proximally located 10° Herzog Bend eases implant insertion and minimizes fracture displacement during implantation
  • Uses standard TRIGEN captured locking screws for system compatibility
  • Titanium alloy for strength, flexibility and biocompatibility

FAQs

Frequently Asked Questions

1. Where are the proximal and distal locking holes on the META-NAIL Tibial nail?
The dynamic hole is located 10mm from the top of the nail. The three (3) static oblique locking holes follow at 23, 30, and 40mm from the nail's top. An additional proximal static lock may be placed at 17mm when used with the Nail Cap Set Screw. The distal most ML hole is 5mm from the tip of the nail with an AP hole at 15mm and another ML hole at 25mm.

2. When is the Tibia Extension Drill Guide used instead of the Standard Drill Guide?
In a Tibial nail case, the Tibia Extension Drill Guide lets your surgeon lock the nail distally with the leg in extension. The long barrel of the Standard Drill Guide is intended for a percutaneous approach to the knee and will impinge upon the distal femoral condyles if your surgeon attempts to fully extend the leg. Even if the leg does go into extension when using the Long Handle, there is a good chance that it might damage the articular cartilage of the femoral condyles. Strongly recommend against locking in full extension with the Standard Drill Guide. The Extension Drill Guide is too short to be used with the Retrograde Femoral Nail.

3. Can the META-NAIL instruments be used with the standard TRIGEN◊ Knee Nail?
Yes, the new META-NAIL instrumentation is compatible with the standard Knee Nail implants. However, the reverse is not true. You cannot use the standard TRIGEN Instrument Set (7163-1326) to implant the META-NAIL Tibial and Retrograde Femoral Nails. This is because the Guide Rod will not pass through the Quick Bolt which is not cannulated.

4. How much intraoperative compression can you get when using the Compression Locking feature of the META-NAIL Tibial Nail?
You can get up to 7mm of intraoperative compression using either the Disposable Compression Driver (7165-4517) or the Nail Cap Set Screw (7165-6000).

5. Why did we move the dynamization slot from the bottom of the Knee Nail to the top of the META-NAIL Tibial Nail?
The META-NAIL is designed with the specific purpose of providing optimal fixation for metaphyseal fractures with an intramedullary device, including the distal metaphysis. In doing so, the designing surgeons insisted that the very distal static locking options could not be compromised. In fact, it was improved over the Distal Tibia Nail with the addition of a locking thread in the most distal hole. By placing the slot in the most proximal location, it can now serve as three features in one: a compression feature, a dynamic locking feature, and a static locking feature when used with the Nail Cap Set Screw.


6. Why is there no dynamization slot in the META-NAIL Retrograde Femoral Nail?
Because of a relatively low rate of non-union and propensity for healing, femur fractures rarely need to be dynamized. Even epiphyseal fractures tend to heal fairly well. In comparison, tibia fractures have a much higher non-union rate and studies show that dynamization is used more frequently to achieve successful fracture healing. The key to preventing non-union is to minimize shear forces and encourage early motion. The threaded locking hole/screw interface of the META-NAIL Retrograde Femoral Nail allows for early motion as well as a reduced likelihood of fragment translation due to shear. This all adds up to a reduced need for a dynamic locking hole in the nail.

7. Is the META-NAIL locking screw mechanism the same as the one for the PERI-LOC◊ system?
No, with the PERI-LOC system the conical threaded hole only allows the locking screw to advance so far before it becomes statically locked. The conical screw head can only advance a finite distance before it becomes too wide to go any further. At that point, the threads of the screw hole match up with the threads of the screw head to prevent toggle and back-out. The META-NAIL locking mechanism is really designed to prevent fragment translation and loss of reduction by way of screws that thread into the nail but that are not statically locked like they are with the PERI-LOC system. The greater the degree of static fit between screw and locking hole, the greater the chance for implant breakage and screw cross threading. The META-NAIL system reduces that likelihood by allowing for some movement, but by reducing screw back-out via threads that match up. In addition, each nail has at least one hole with a polyethylene bushing in it to capture the locking screw and create a fixed angle device. This screw increases the resistance to toggle and back-out of the other screws thereby increasing the overall stability of the construct.

8. Why aren't there poly bushings in every threaded hole?
In the tibia nails, the first and second screws have the most difficulty with screw back out problems. The first screw can be locked with the Nail Cap Set Screw and the second is locked with the poly bushing. The third and fourth screws are in more diaphyseal bone with better purchase and are threaded without poly bushings to prevent screw translation.
In the retrograde nail there are threads only in the most distal, transverse hole. This screw may be locked with the Nail Cap Set Screw so that it will not back out. The second and third oblique holes are equipped with threads and bushings to prevent translation and backout.

9. Are there any differences in strength between the META-NAIL Tibial Nail and the Knee Nail in tibial mode?
Our biomechanical testing data show that there is no adverse difference in strength between the two (2) nails. In fact, in some cases the META-NAIL Tibial Nail actually tested to be stronger than the standard Knee Nail. The testing regimen included axial load, torsion and bending strength.

10. Does the new proximal locking screw configuration of the META-NAIL Tibial Nail place any neurovascular structures at risk?
Damage to the peroneal nerve is a major concern when nailing fractures of the proximal tibia. The more a nail is countersunk, the closer the locking holes come to interfering with the nerve's trajectory. As a result it is generally recommended to avoid over insertion (2-3cm) of a tibial nail. The actual screw trajectory of some competitive nails has been shown to place the peroneal nerve at higher risk the more the nail is countersunk. The trajectory and location of the META-NAIL Tibial Nail's proximal locking screws did not exhibit the same tendency towards an increased risk for nerve damage when implanted to the same depth as the DePuy nail during lab/cadaver testing. As always, care should be taken to minimize potential risks, but the META-NAIL Tibial Nail's locking configuration places screws far enough away from the nerve's path to avoid serious complications.

Design Rationale

Design Rationale for TRIGEN META-NAIL Tibial and Retrograde Femoral Nail System

Metaphyseal fractures are typically associated with high energy injuries and, as such, are often comminuted. Unstable fractures are difficult to treat given the tendency of the fragments to shift around. The emergence of the fixed angle construct, or locking plate, has gone a long way towards simplifying the fixation of these fracture types. The inherent advantage of the locked plate is the fact that the screws anchor to the plate and hold the fragments in place following reduction. This technology is currently unavailable in intramedullary nails outside of using an additional screw or end cap to lock down a locking screw and prevent it from moving. The locking concept renders fractures that were previously “un-nailable” much more readily treatable with an intramedullary device.

The TRIGEN◊ META-NAIL◊ Tibial and Retrograde Femoral Nail System is the first of its kind on the market as it incorporates the advantages of multi-planar fixation with the stability of a fixed angle-type device. The META-NAIL locking mechanism doesn't require usage of additional screws or end caps as the locking screws simply thread into the threaded holes or are captured by polyethylene inserts. This locking mechanism then prevents fragments from translating and helps the fracture to heal in a more stable environment. The META-NAIL system incorporates a true “interlocking” locking screw concept with a minimally invasive, percutaneous approach to preserve blood supply and deliver highly stable fixation.

The propensity of most metaphyseal fractures for angular deformity can turn intramedullary nail insertion into a complicated procedure. Not only must the fracture be reduced anatomically, but that reduction must be maintained during the entirety of the procedure in order to ensure proper nail passage. When manual reduction is ineffective and implant trajectory difficult to control, the blocking screw can act as a buffer to redirect the nail's path. Strategic placement of the blocking screw in either the AP or ML may help to avoid a potential mal-reduction. To date this has been a free-hand procedure with an understandable margin of error. The blocking screw targeting instrumentation included in the META-NAIL system removes the fiddle factor associated with the procedure and further establishes the META-NAIL system as the next generation of intramedullary nailing.